The term strand as used throughout this application is intended to include wood elements known in the trade as strands, wafers, clipped veneer, and the like and particularly long strand which define strands having axial lengths of at least on average above 6 inches (15 cm).
Many different devices have been proposed for orienting strands for forming of oriented strand boards. Some employ discs, others employ plates or partitions, but in each system the object is to obtain the best orientation of the longitudinal axes of the strands substantially parallel to each other and usually to the longitudinal axis of the panel being made.
One such device is shown in U.S. Pat. No. 3,115,431 issued Dec. 24, 1963, to Stokes et al. This device includes the plurality of intermeshed rotating discs mounted on a plurality of substantially parallel side-by-side shafts positioned in a plane. The discs on the shafts are uniformly positioned intermediate discs on their adjacent shafts. In the arrangement described, the discs on adjacent shafts turn in the same direction, except for the last discs in the sequence which turn in the opposite direction. This type of arrangement (hereinbelow referred to as the Stokes' arrangement) has been found satisfactory particularly for use with long strands. The disclosure of the Stokes et al. patent is incorporated herein by reference.
Another similar device is shown in the Burkner U.S. Pat. No. 4,666,029 issued May 19, 1987 but wherein the discs on adjacent shafts are arranged in pairs in side by side relationship with the discs forming one of the pairs defining one side of an orienting passage and the discs forming the next axially space pair defining the other side of the passage. This arrangement (hereinafter referred to as Burkner's arrangement) is also satisfactory but the Stokes' arrangement is less complicated and appears to be about as effective in aligning the strands as the Burkner arrangement. The Burkner et al. patent is incorporated herein by reference.
U.S. Pat. Nos. 4,380,285 issued Apr. 19, 1983 to Burkner and 4,623,058 issued in Nov. 18, 1986 to Bossier each shows a combination of discs mounted on spaced parallel shafts and positioned above and intermediate stationary substantially vertical guide walls forming opposite walls of orienting passages through which the strands fall and are oriented. This type of orienter also has not been found to be particularly satisfactory for producing an end product with the required orientation and strength.
Canadian patent 920,529 issued Feb. 6, 1973 to Turner et al. shows yet another form of orienter wherein partition walls are designed to move to prevent plugging.
U.S. Pat. No. 3,807,931 issued Apr. 30, 1974 to Wood et al. describes another form of orienter which use a number of vertically stacked decks each formed by stationary vertical fins each provided with a vibrating cap that improve movement of the wood particle there between. Each deck has a number of fins that is a multiple of the number of fins in the deck immediately above it so that the fins on the upper deck directly overlie corresponding fins on the lower deck and the the flow of strands is divided by the upper deck and the divisions so formed further subdivide by the next lower deck. In this device, the spacing between the fins on the top deck is about half the average length the strands that are to be oriented and the spacing between the upper and lower deck is defined as the distance greater than the average length of the strands. The orienting system of this patent clearly would not be effective for long wafers nor would it function well for conventional length (3 to 4 inch) strands.
U.S. Pat. No. 4,494,919 issued Jan. 22, 1985 to Knudson et al. describes another form of apparatus for orienting strands particularly suited to orienting and distributing of long strands.